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Description

My goal is to build a four bit computer using recycled, re-purposed and just plain junk as the main construction material. Why? Well, the cardboard is free as my workplace puts it in the dumpster and I do not have the funds to buy better material. A very green build indeed. Except for the ALU, all logic cells are constructed on individual cardboard pads as basic Nand, Nor or other gates as basic building blocks.
This method of construction is open to anyone of any age who can solder and all circuits are wired point to point, no PC boards. A great hands on learning aid to see how digital logic works at the gate level. No black IC packages will be found at the end of this project.

Details

The heart of this project is the Cardboard Logic Pad or CLP. With this construction method, any logic gate can be produced and pads can be combined for more complex logic circuits. This method started out by using thumb tacks pressed into wood panels. That method was not well suited to easy circuit modification and logic gates could not be inserted or removed easily. Using cardboard as a base material has proven to be easier to work with and is lighter in weight.

Components

Build Instructions

The Cardboard Logic Pad - The basic logic building block for the construction of IO

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Step 2

This is the start of building a Cardboard Logic Pad or CLP for short. The cardboard is found as scrap and the paper fasteners are from any local office supply or big box store. These fasteners take solder very well.

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Step 3

Select the gate circuit that is desired. In this case I am using my basic Nand gate circuit using a npn transistor and input diodes.

As long as this project is indoors in a controlled environment I don't see a problem for a couple of years at least. I figure that if I wanted to preserve the finished project then I could spray a nonconductive coating to seal it later.